Understanding Power Phase
Understanding power phase is integral in the process of choosing the pump configuration that is right for you.
Unlike direct current (dc) power, which provides constant levels of voltage, alternating current (ac) power follows a waveform alternating between positive and negative voltage. Because ac power is easy to produce and transmit, it is the power of choice to transmit to homes, commercial buildings, and industrial facilities.
When talking about alternating current, phase is used to describe an instantaneous point on a waveform cycle. When all of the instantaneous points are taken together over a completed cycle, the result is referred to as 360° of phase or more generally a phase. It is standard to have the reference be the phase that passes through the origin. This standardization gives the phase the form of a sine wave and creates nodes, or points of 0 current, at 0°, 180° (π), and 360° (2π). As the wave passes from crest to trough the amount of current provided matches proportionally.
The most common power phases are single- and three-phase. When dealing with multiple phases, the offset in time or degrees between the same reference points on two waves traveling at the same frequency is called the phase difference. Phase difference can tell use the amount of time or distance between maximum current draw. Consequentially, the waves behind the reference phase are called the lagging phase, and the wave before the reference is called the leading phase. Refer to Figure 1 for a representation of each of these terms on a standard three-phase waveform.
Single Phase Power
Single-phase power is commonly found in residences and commercial buildings and is primarily used for powering small appliances under 1000 watts. This configuration may either be a simple 120V or a split phase configuration with 120/240V. Single phase is either a two or three wire ac circuit. In older wiring designs there is one power line and one neutral line. New designs add an earth to ground connection to improve safety.
Although single-phase power is available almost everywhere, it is not recommended for use on motors greater than 5HP. When comparing two motors with the same horsepower rating, the single-phase motor will draw significantly more current than the three-phase motor. Because of the larger current draw, larger and therefore more expensive windings are required. In addition to being physically larger, single-phase motors are generally less efficient and require a starting capacitor which adds more to the cost. For these reasons, we recommend that three-phase motors be used when available. See Figure 2 below for more specific waveform configuration and power phase information.
Single phase 120V motor rotation cannot be changed without much difficulty after the motor has been manufactured. It is absolutely necessary to make sure that the rotation of the motor matches the desired rotation of the pump impeller.
Three Phase Power
Three-phase power is usually found in commercial and industrial facilities where large equipment is operated. Three-phase is usually distributed in the Wye configuration with five wires. Three of the wires carry current; the fourth wire is a neutral, and the fifth wire is an earth-ground wire. In the less-common Delta configuration there is no neutral wire. Although other configurations exist we will not discuss them in this introduction.
Three-phase power, where available, will provide smooth, more balanced, and frequently less expensive motors and motor operation. This is due to the fact that three-phase power has three identical overlapping waves. The wave cycles are evenly spaced 120° apart so the supplied power remains relatively constant when compared with single-phase power. When phase one is at a node, the next phase is only 30° and approximately 5.5 seconds from reaching its crest, and so on for each passing phase.
When compared to a single-phase power supply that uses the most common configuration (phase and neutral), a three-phase supply with no neutral, and the same phase-to-ground voltage and current capacity per phase can transmit three times as much power using just 1.5 times as many wires. Because of this, the ratio of capacity to conductor material is doubled making it possible to use smaller, less expensive wiring. See Figure 3 below for more specific waveform configuration and power phase information.
Understanding alternate phase and wiring configurations is key to finding the best configuration for your application. Available power phase can have a major impact on your choice of motor and pump design. Understanding these basic principles will help you to understand motor efficiencies, start-up operations, and operation/maintenance costs. Please let us know if you have any questions about the ideal configuration for you.
To learn more, check out our post on Pump Power Frequency and Alternating Current (AC).
51 Comments
I didn’t realize that three phase power configurations on well pumps uses overlapping waves to provide constant power. My sister is having a home built for her family in the hills. Hopefully, she can use this info to choose a set up that can supply her family with constant water. Thanks!
You are welcome! Good luck with your project and a steady flow of water!
Hi,
I have a 3hp pump and also have taken 3 phase power connection. Is it efficient to go for 1 phase pump or 3 phase pump ?
Victor,
It sounds like you are saying that the pump requires a three HP motor. If you have three phase power available, I would recommend using it over single phase power for the motor as long as it is not significantly more difficult to install.
Good luck!
Can single phase submersible pump runi continuslly a full day
Ganesh,
Thank you for your comment. Yes, a single phase motor can run continuously.
One of the water pumps in the city broke a week ago and it got me curious about them! I didn’t know there were different power phases for pumps before. That is really cool that the most common power phases are single and three-phase! Thank you for all the information!
Thank you for the comment Deb! We are glad you found the article useful.
Hi We have single phase power available but we want to use a 3 phase in the pump. Is this possible. What is the life span of a 240 vs a 3 phase pump?
Thank you
Miguel,
Thank you for your question. It is not possible to operate a three phase motor on single phase power without a piece of equipment called a phase converter. Digital phase converters are commonly added to variable frequency drives (VFD), and can be purchased from most motor shops or local electrical contractors. Keep in mind that if you are using a variable frequency drive, you need to either purchase a motor with a shaft grounding ring, or install a shaft grounding ring on your existing motor to insulate the bearings from stray voltage.
Here are a couple of sites to check our for more information.
https://wiki.openelectrical.org/index.php?title=Phase_Converter
http://www.est-aegis.com/datasheets/AEGIS_HVAC_White_Paper.pdf
Let me know if you have any other questions.
Hi,
I have a scenario in which I have a single phase connection available.
I need to use a centrifugal pump of 5 hp which will pull water and throw to a stream of 600 ft.
My queries are
1. Does single phase hold the load of 5 HP.
2. If yes will 5 HP pump be good enough to cover the 600 ft distance.
3. What can be the atlternative with a limitation of having a single phase connection only? Can a phase converter helpful in this scenario in order to make it three phase and use a 3 phase pump?
Appreciate a swift response.
Thanks & Regards,
Najam Jamal
I received a chart on how to obtain a meter. I don’t which one one should i go for. Is it single phase or three phase meter. Presently, i have a 0.5 horse power pumping machine using to pump water. Hopefully, to join this with AC, water heater and electric cooker. I don’t know whether single phase meter can take care of all aforementioned items.
Very helpful information. I learned a lot from your article.
Thanks
Thank you Hussain, glad the article was informative and useful!
What 3 phase cable size do I need to run two 5.5 KW 3 phase water pumps running in tandem at a distance of 450yards from power supply. The supply is 240v.
Many thanks
Neil,
Thank you for your question. To be able to size cable, you would also need to know the following information.
-Amp draw of your motor.
-Maximum ambient temperature.
-Allowable voltage drop (usually either 3%-5% of the source voltage).
If you are powering both motors from a single power source/cable, you would need to rate the cable for both amp draws, or double the cable size requirements of a single motor.
Hopefully this helps.
I want to install a 3 phase (208v) standby generator at my residence. The grid is a delta configuration or stinger leg. The only 3 phase equipment is a submersible well pump. Does the standby generator need to produce power with one leg as a stinger?
Jeff,
Thank you for your question. If the motor on your submersible pump is 3 phase, you will need to use the high-leg of your generator to operate it.
Here is a helpful article that may explain things more completely.
https://en.wikipedia.org/wiki/High-leg_delta
Hopefully this helps.
I would like to know single phase and three phase submersible pump advantage.
If I use three phase motor, my power cost comes down? or single phase pump will consume higher current?
I want to run single phase motor pump which is 5 HP and it draws 30 amps and it is 4000 feet away from my farm , I want to run it from my farm so how do I choose the cable size to supply 30 amps to motor
Janak,
Thank you for your question. I would recommend reaching out to a local wire/cable provider to see what they would recommend based on what they stock. There is a little more to take into account than what you have provided. I would recommend Cerrowire as a good online vendor.
https://www.cerrowire.com/
They will need the following information to size the proper cable.
Length of cable run
Phase of power
Construction of conductor (Copper or Aluminum)
Type of Installation (buried, conduit, overhead)
Voltage
Voltage drop (3% recommended)
Current at the end of run (motor voltage plus safety factor)
Number of parallels (they can help you with this portion)
I hope this helps!
While using a 3 phase 5HP submersible agricultural pumpset, at times 2 phase is provided. An autostarter switch is used, which means the pumpset may run on the 2 phases and burnout.
Please name and describe a tool to prevent 2 phase run and burnout.
Can a protector be installed within the motor to stop it when 2 phases alone are provided?
Mark,
I would recommend contacting your power provider and see why the third leg of power is being lost. There are protectors you can purchase. I would recommend Googling a electrical control panel shop in your area. They should be able to provide a control to prevent the pump from engaging when you are having power issues.
how can i use 3phase 3hp submersible motor pump if Only available 2Phase current is there any alteration
hi!
I would like to ask if there is any way i can use vfd in my single phase water pump. my power source is 3 phase but the vfd available in our local store has single phase input and 3 phase output. how can i use this vfd in my single phase water pump?
I will be appreciate your response. thanks
Jun,
Thank you for your question.
There are a few options to convert three phase incoming power to a single phase output. There are drives available with these capabilities built in, but here is a quick summary of a few ways the conversion could take place.
1. Convert the incoming three phase AC power to DC using an electronic rectifier, and then convert the DC power to single phase AC using a single phase inverter.
2. Use a single phase transformer across two phases of the incoming power. This is only acceptable up to about 400 volts.
3. Use a open delta transformer. Using this transformer effectively double the acceptable voltage rating as compared to a single phase transformer.
I recommend talking to a local control shop for their recommendation. All of these options should be reviewed and implemented by an experienced electrician.
Have a great day!
Three or single phase pump
Which pump give more water having same HP
Prashant,
Please note that the phase is a characteristic of the motor and not the pump. At the same HP, the phase will have no effect on the performance of the pump.
Have a great day!
How to identify the motor are of single phase or a three phase.if there is no name place on motor?
Using multimeter…..?
Very helpful information. Thanks for sharing it with us.
Brian
For my new home 15 years ago the well installer talked me into a VFD 3phase system instead of a single phase and traditional expansion tank. Since then, the well company has had to replace the franklin VFD unit 7 times due to failures, some months apart, some lasting a few years. I have spent nearly $8,000 in VFD replacement and service calls. There are multiple ground rods on the electric system and lightning/surge protection on both the VFD incoming line, line from well, and one on the power supply to the VFD. The failures always occur during a severe rain or lightning storm. The last controller cost me $3200, which is completely absurd. The well installer would not come out until I paid him up from for a controller that had failed 2 months earlier. Franklin has changed their warranty from 5 yrs to 3 years. I cant pay $3200 every 3 years for a failed controller.
Do you have any suggestions on replacing the franklin with a cheap alternatve or should I remove the system and replace it with single phase equipment?
Bart,
I’m sorry, that sounds very frustrating. I’ll send you an email so we can discuss this a little further.
Best regards,
Brian McWhorter
Hi my borehole is 114 meters deep i have a Franklin 2Hp motor and a 27 stage wet end as you see there is a lot of weight so not easy to lift . The BEST protection i have found to date is SIMPLE the supply to my control box has a 15 A socket outlet and 15 A Plug top IF any lightning on the horizon i pull the plug out i have the normal under and over voltage protection as well. My pump has been down 28 years and no prob and runs about 5 to 6 hours a day,
i have worked on HIGH voltage most of my life and this to me works and others around me have payed the price Good luck
Is there a line of Single Phase 220V water pumps ? I’m looking to replace a gas powered pump, but only have single phase 220V 50AMP power. Do you have a recommendation ?
Blair,
Thank you for your comment.
If your flow and pressure requirements are low enough to keep the motor size below the 7.5 – 10 HP range, there are numerous options to choose from. Any pump manufacturer can supply a pump with a motor that will operate on single-phase 220-230V power. However, without knowing more about your application and current pump design, I cannot recommend anything specific.
Best regards,
Brian McWhorter
Thank you so much for your prompt reply! The application is as follows :
We have a 20,000 gallon tank that is 6 feet deep with a draw at the bottom. The pump is at the top of the tank. The input to the pump is 2″
The pump needs to pump out 2″ diameter pipe 200 feet, then up 30 feet.
I’m hoping to get 50 gal/min at 80 PSI at the end of the pipe.
Thanks
thanks
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I work for an oil & gas operator in the water management dept. We are trying to run power to our water wells that we use to fill our frac pits. We use 40HP pumps in most of these wells, however one water well location the local power provider has told us they cannot provide 3 phase power to, but they can run single phase, if we do not run anything higher than 25HP off of it, with a phase converter and VFD, of course. I have been led to believe that we may can have a 25HP pump manufactured that would be able to produce the same flow rate as a 40HP. This all sounds great to me, but with my limited knowledge in the areas of electrical power and water well pumps, I felt it would be better to check with the professionals first. What are your thoughts/advice on this situation?
Seth,
Thank you for your questions. It sounds like you are asking two separate questions.
– The size of the motor you can run off of the phase converter is based on the length of the power lines, voltage of those cables, and the available amperage. I would recommend reaching out to the panel manufacturer with this question.
– If the pump required the larger motor to meet your original conditions, it will not work with the smaller motor. You will either have to find a smaller pump, or trim the impellers on the existing pump. Either way, you will have a significant reduction in performance.
Good luck!
Great short article,
I’m installing a solar well pump in a remote area, 1.1 kW with what I designed initially as a 2.4 kW PV system. The way I understand it, the single phase pump would require as much as 3 kVA to start which will probably be an issue.
Would a 3-phase pump (same power) limit this starting requirement so that 2.4 kW from the solar panels would be sufficient? (inverter can switch 1P to 3P relatively easily).
If yes, is 3-phase a general recommendation for solar pumps?
thanks for any info on this subject.
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Thank you for taking the time to read it!
Can a single phase submersible pump run using 3 pH control panel connections
Stephen,
Yes, in essence you run a single-phase motor on a three-phase supply by only using one phase and neutral provided the voltage to neutral matches the motor rating. Make sure you ensure proper earthing and protection by MCB to the motor.
You may want to have a local electrician make the actual connections.
Good luck!
very helpful blog – I have 200Amp, 120/240V, single phase power available. want to run 3-hp submersible sanitary pumps. Can get either 1ph or 3 ph pumps. for 3ph pumps would use VFD to convert to 3ph. would 1ph pumps be better or would 3ph pumps with VFDs be better?
thanks
Thank you for taking the time to read the article and for your question.
If you only have single-phase power available and will only need 3 HP to meet your pump’s demands, you are better off to not try and convert to three-phase power. It would be cheaper and easier to stay with single-phase power for the pump and controller.
As a tip, many submersible sewage pumps are not designed to run on a VFD. If you are going to use VFDs, make sure you confirm that the motors are inverter duty rated and that the conditions do not push the motor into the service factor. Service factors cannot be used when being operated through a VFD.
Good luck!
I have single phase submersible motor and three phase supply can give three phase to single phase motor
HEllo ,
we used gear pump of up to 15LPM in our machine .
Every time customer dont have three phase power so they using it on single phase but some times its working and some time its not working . on which factor gear pump can purchase . if pump is free from start we have doubt on life of pump.
plz note customer max using 50bar on pump.
please suggest on it .